Feeder control system for an automated blender system

ABSTRACT

An improved feeder control system is disclosed. The system implements an incremental metering process that incorporates the standard deviation of the material feeder. By intentionally initially under metering at a level corresponding the standard deviation of the feeder, and then subsequently metering a more accurate delivery of materials is achieved. Additionally, the system implements a system for correcting for metering errors caused by gate cycles delays. By incorporating offsets into a feed time when gate cycle time is larger than the feed time, error caused by significant gate cycle times is cured.

BACKGROUND

[0001] This invention relates to a method and apparatus for moreaccurately measuring and blending particulate material.

[0002] In the past, slide gate feeders were not very accurate atdispensing small amounts of material. The use of auger feeders wasrequired in order to dispense small amounts with any accuracy. This wasprimarily due to the mechanical standard deviation of the slide gate. Ifa slide gate is repeatedly opened for a precise amount of time theamount of material that is dispensed through the gate varies. Thisvariation is related to the amount of time that the gate is open. If agate opens for a small amount of time (in milliseconds) a smaller erroroccurs than if the gate opens for a large amount of time (in seconds).This error is caused by the way that material flows through the hopper.Opening the gate for small amounts of time doesn't give the material inthe hopper a chance to move. Instead it slices the material present atthe gate. When the gate opens for large amounts of time the materialflows down the hopper. This flow is not perfect in any hopper due to theshape of the material and/or the fact that the material tends to surgein pulses. If a gate opens for several seconds, the material surgesseveral times; sometimes it will surge three times, while other times itwill surge two or four times. This variation causes significant errorduring metering. Typically, a control algorithm will keep metering untilthe appropriate target weight is reached; but this results inovershooting the target and therefore providing surplus material. Thekey is to prevent overshooting caused by this deviation. To compensatefor those surges and overfills, some systems employ augers. An auger isunaffected by the material surging in the hopper because the material,in the auger system, is dispensed at the end away from the materialsurging from the hopper. Therefore, auger systems were the preferredmethod of metering small amounts. The problem with auger systems is thatthey have to be sized correctly. If an auger is too big for thematerial, then the resulting standard deviation will also be enormousand cause overshooting the target weight.

[0003] Additionally, when metering uses a gate feeder, the gate feeder'scycle time (the time to open and close the gate) may prevent anymaterial from being dispensed. When metering small amounts, the feedtime is small and may be smaller than the cycle time. If the feed timeis smaller than the cycle time, then no material will be dispensed.Consequently, if a control system designates a feed time for a gatefeeder smaller than the cycle time, then the control system willmistakenly believe that material is being dispensed.

[0004] Since gate feeders do not have to be sized to correspond todifferent materials, it would be desirable to use gate feeders to feedmaterial.

[0005] It is an object of the invention to provide a method andapparatus for accurately metering flowable, bulk solid material using aslide gate feeder that solves to an extent the above noted pitfalls byincorporating the standard deviation of a feeder into the meteringprocess. In another aspect the invention incorporates consideration of afeeder's cycle time into the metering process.

[0006] In another aspect, a blending system for proportionatelycombining materials method includes metering a feed material includingthe steps of: designating a recipe and a batch size, calculating targetweight amounts of each ingredient material, calculating a correspondingfeed time for each material feeder, and metering each feeder. The feedtime is calculating using the feeder's material flow rate, an initialtarget percentage of the target weight, which corresponds to an offsetfor the standard deviation of the feeder, and compensating for thefeeder's gate cycle time.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is a schematic illustration of a blender control systemaccording to a preferred embodiment of the present invention;

[0008]FIG. 2 is a representation of the blender apparatus data structureof a blender control system of FIGS. 1 and 6;

[0009]FIG. 3 is a representation of the recipe data structure of ablender control system of FIGS. 1 and 6;

[0010]FIG. 4 is a flow chart of the steps taken by a blender controlsystem of FIGS. 1 and 6 in making a batch from a recipe;

[0011]FIG. 5 is a flow chart of the steps taken by a blender controlsystem of FIGS. 1 and 6 when calculating the feed time and adjusting fora gate cycle time by temporarily doubling the cycling time;

[0012]FIG. 6 is an illustration of a blender control system according toa preferred embodiment of the present invention; and

[0013]FIG. 7 is a flow chart of the steps taken by a blender controlsystem of FIGS. 1 and 6 when calculating the feed time.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] A first aspect of the present invention is to increase theaccuracy of fed material through a slide gate. A slide gate's mechanicaldeviation causes inaccurate measurements of fed flowable, bulk solidmaterials, e.g., pelletized plastic resins, and causes overshootingtarget amounts of material. In this aspect of the present invention, theslide gate's mechanical standard deviation is measured and adjusted forin the feed-control algorithm. This adjustment prevents overshootingcaused by this deviation.

[0015] Typically, a control algorithm will keep metering until theappropriate target weight is reached; but this results in overshootingthe target and therefore providing surplus material. The controlalgorithm of the present invention instead meters to a percentage of thetarget weight based on the standard deviation of the gate and entered asa parameter in the control system. Based on the Gaussian distributionprincipal, thirty percent (30%) of the time the actual meter will beapproximately equal to the target, thirty-five percent (35%) of the timeit will be high, and thirty-five percent (35%) of the time it will below. Basically thirty-five percent (35%) of the time the first meterwill be within the acceptable final desired target, sixty-five percent(65%) of the time the meter will come up short of the final desiredtarget and have to remeter, or retry. The main difference is that whenthe blender retries to finish the meter it only has to dispense a smallamount. Therefore, the feed time is smaller (milliseconds) and willproduce a much smaller standard deviation on the retry. This generates ahigher accuracy without overshooting the target. The sacrifice is thatthe remetering process takes more time (because of retries) than themetering process of the traditional algorithm. (Additionally, a blendingsystem may be designed to mechanically offset this additional time bythe ability to make larger batch sizes.) The result is a blender systemsubstantially capable of metering small amounts of material from anyfeeder. This result substantially eliminates having to size augers or toadjust gate stops as in the past. During proper operation, it is normalfor each supply hopper to retry one or two times. The control algorithmis flexible and can be adjusted to accommodate various feed mechanismsand the value for a percentage of the initial target weight(corresponding to the calculated standard deviation) is adjustable.

[0016] Another aspect of the present invention incorporates a feeder'sgate cycle time in the control of an accurate feeder control system. Afeeder's, therefore a blender's, accuracy is dependant on accommodatingfor the gate cycle time in the control of the feeder. Gate cycle time ismeasured at the factory and is design, not blender, dependant. Typicalgate cycle times are fifty to one hundred (50-100) msecs. depending onthe cylinder design. When the gate opens for a large amount of time thegate cycle time is negligible; but when metering small amounts thegate's cycle time dramatically effects the results. When calculating thefeed time for each meter, the blender control system offsets the feedtime by the gate cycle time. Another embodiment of the present inventionadjusts for gate cycle time by temporarily increasing the feed time. Asindicated above, if the gate cycle time is short then this can impactthe amount of material fed (i.e., frequently less than the feed time).If, after a number of retries, the target weight has still not beenattained, then the gate cycle time is temporarily doubled and then usedto offset the feed time to allow the gate to remain open longer.

[0017] The blender system performs the following steps during a normalbatch process:

[0018] Calculate target weight amounts based on the Recipe and thecurrent Recipe Format Options

[0019] Empty weigh hopper

[0020] Calculate the feed time for the first feeder (adjusting forstandard deviation of meter and adjusting for gate cycle time)

[0021] Meter the first feeder

[0022] Determine if the feeder needs to add more material to reachdesired target weight and, if so, re-calculate feed time based onremaining amount and retry. Repeat until material reaches desired targetweight.

[0023] Repeat until all ingredients have been added.

[0024]FIG. 1 and FIG. 6 illustrate blender control systems 10 and 20that can be used as embodiments of the present invention. In thefigures, a supply hopper 104 stores the ingredients to be weighed. Aslide gate 102, the feeder, acts as a flow regulator that controls thespeed of flow of the material and is positioned at the outlet of thesupply hopper 104. The slide gate 102 is able to vary the amount ofingredient supplied by varying the time that it is open. In anembodiment of the invention shown in FIG. 1, a feed tube 106 acts adelivery mechanism where one end is positioned at the outlet of theslide gate 102. In another embodiment as shown in FIG. 6, material isgravity fed and therefore may not require a feed tube 106. A weighhopper 110 acts as a receiving vessel from the other end of the feedtube 106 and has a weighing capability and is positioned on top of aload cell 112. A dump gate 116, a flapper, acts a flow regulator and ispositioned in between the outlet of the weigh hopper 110 and the inletof the mixing chamber 114 which acts as receiving vessel for ingredientsin a batch. A computer system 120 (described below) is connected toslide gate 102 and dump gate 116 via control lines 122 and controlstheir opening and closing. The computer system 120 is also connectedthrough other control lines 122 to and receives weight information fromthe weigh hopper 110 and load cell 112.

[0025] When a batch of a recipe is made, an ingredient is delivered fromthe supply hopper 104 to the weigh hopper 110. The computer system 120controls the amount of material delivered to the weigh hopper 110 bycontrolling the slide gate 102. The computer system 120 monitors theweight of the weigh hopper 110 and when the desired, or target, amountof material is fed, the computer system 120 opens the dump gate 116 anddelivers the material into the mixing chamber 114. This process offeeding an ingredient is repeated for each ingredient remaining in therecipe. Once the recipe batch is complete, the material in the storagetank is ready for delivery down stream and another batch of this, oranother, recipe can be made.

[0026] In a preferred embodiment, the supply hopper 104 is and should beof a scale appropriate for production.

[0027] In a preferred embodiment, the feeder, or feed delivery controlsystem, 102 is a pneumatic slide gate. Other embodiments may includeother slide gates or other feeder systems, such as an auger or screwmechanism.

[0028] In a preferred embodiment, material is gravity fed and the weighhopper is disposed under the output of supply hopper so that the weighhopper receives gravity fed material from different supply hoppers. Inan alternative embodiment, the feed delivery system 106 is a feedingtube or a screw mechanism.

[0029] In a preferred embodiment, the weigh hopper 110 is a standardweigh hopper. The capacity of the container should be of a scaleappropriate for production.

[0030] In a preferred embodiment, the load cell 112 is a strain gaugeload cell.

[0031] In a preferred embodiment, the second feed delivery system 116,that delivers material from the weigh hopper to the mixing chamber, is adump gate. Many other techniques are common known in the art to satisfythese requirements.

[0032] In a preferred embodiment, the mixing chamber 114 is standardmixing chamber with a capacity of scale appropriate for production.

[0033] In a preferred embodiment, the computer system 120, whichincludes both software and hardware, is an Allen Bradley MicrologixControl system. Other embodiments may include other computer systems,where the blender control system may be incorporated into either thehardware or software systems. For example, the computer system maybeimplemented in a person computer, industrial computer, networked system,computer server, distributed logic system, a remote access computer,local area network (LAN), wide area network (WAN), or a programmablelogic circuit (PLC). This computerized control system 120 controls andmaintains information about the different blender apparatus (i.e.,hoppers, feeders, etc). The computerized control system 120 alsomaintains information about automated blending operations, includingmaintaining information in the form of recipes and other blenderapparatus and may be stored in data structures, as represented in FIGS.2 and 3. Users interact with the computer system through the use of atouch screen display and/or a keyboard and monitor. New recipes andother system parameters are entered by this touch screen display and/ora keyboard into the computer system 120. In another aspect, the computersystem is remotely accessible. Additionally, program control is donethrough the touch screen and/or keyboard. In a preferred embodiment, thecomputer system 120 is menu driven allowing control and display of thesystem in response to menu options. Furthermore, entry or modificationof system variables in data structures in done in response to differentwindow options.

[0034]FIG. 2 illustrates a blender apparatus data structure, which is apreferred embodiment of a data structure that retains information aboutthe blender system. Stored in memory this data structure maintainsinformation about the feeders and other system variables that are notrecipe dependant. As shown in FIG. 2, the data structure contains thefollowing information: the number of supply hoppers 202, the measurementunits 206, and for each supply hopper the structure maintains: feedertype 208, cycle time 210 (the amount of time to open and close thefeeder), enable retries 212, number of retries 214 (the number ofretries allowed), calibration 216 (the material flow rate), and theinitial target percentage 218 (this is the offset to compensate for thestandard deviation of the feeder and is input by the user). The computersystem 120 permits modification of the feeder and/or other systemvariables. For instance, adjusting the number of supply hoppers 202 andthe predetermined gate cycle time 210 for each supply hopper ispermitted. The gate cycle time 210 has been measured and set at thefactory but might need to be adjusted if the mechanical design ischanged. This setting will depend on the whether the feed system is agate or auger. Furthermore, computer system 120 also maintains, andallows modification of, each feeder type 208 (slide gate, auger, etc),enabling a retry for each supply hopper 212, the number of permissibleretries for each supply hopper 214, and the units of measurement used206 (i.e., pounds or kilograms). The computer system 120 also permits amodification of each feeder's calibration 216. Other embodiments mayvary the number and type of system information retained by the system.

[0035] Additionally, each feeder's accuracy may be tested to determineits standard deviation. By entering a target weight and identifying afeeder to test, the computer system 120 of the blender calculates ameter time based on the current feeder calibration and opens the gatefor the appropriate amount of time. By repeatedly performing this testwith the same target weight and recording the weight of the materialdispensed, the standard deviation of the feeder system can be determinedand later incorporated into the data retained by computer system 120 ofthe blender control system 10. In the preferred embodiment, a calculatedstandard deviation of the feeder is entered and reflected as the desiredcorresponding value as the percentage of the target weight 218. In thismanner, the control system 120 will calculate an initial metering withthis percentage of the target weight as the objective. Then during anyretry, the control system 120 calculates subsequent metering ascalculated based on the target weight minus the amount of materialalready metered. In another embodiment of the invention, the recordationof these test weights, and the calculation and the incorporation intothe system parameters of the standard deviation is done automatically.In a preferred embodiment as commonly known, a feeder is initially setto default value and self calibrates during its first metering.

[0036] A recipe is the desired combination of different ingredientmaterials to make a batch. FIG. 3 illustrates a recipe data structure,which is a preferred embodiment of a data structure that retainsinformation about a recipe and which is maintained in the computersystem 120. The data structure contains the following information: therecipe mode 302, metering order 304, batch size 306, shutdown value 308,the batch ready mode 310, number of ingredients 312, and for eachingredient the recipe amount 314. Although a recipe is a combination ofingredients, a recipe is implemented by describing the recipe in termsof combining different hoppers (which contain the desired ingredients).The recipe mode 302, or the recipe's combination of ingredients, isexpressed in a “Percentage Method,” a “Parts Method,” and/or an “EZMethod.” In the Percentage method, commonly used in an extrusionprocess, a recipe is entered indicating the allocated percentage of eachhopper to be used. The total percentages of each hopper should be onehundred percent. In the Parts Method, commonly used in compoundingoperations, ingredient values are based on “parts” of the whole. In thepreferred embodiment, each part can have a value up to 999.99 and thetotal of all ingredients does not have to be 100. Individual targetweights of each ingredient would be based upon the calculation of theratio of each ingredient's “part” to the total batch size. In the “EZ”mode method, used most often for injection molding, one hopper isconfigured as virgin, one hopper is configured as a regrind, and othersare configured as additives. The recipe for an injection molding processwould have a value for the percentage of regrind, which represents apercentage of the total batch, and a percentage of additives, whichrepresents a percentage of the virgin weight. Each percentage can be upto one hundred percent and the computer system 120 calculates thepercentage of virgin material.

[0037] A recipe contains other system information as well. A recipedesignates the specific order in which the ingredients are added (i.e.,which hoppers are metered) by changing the metering order 304. The batchsize 306 is established and can also be changed. In a preferredembodiment, the batch size 306 is initially factory set dependent uponthe blender type. Other embodiments permit altering additionalvariables, including: changing the inventory shutdown value 308 (whichallows the blender to make a certain amount of material at a time) andenabling or disabling batch ready mode 310 (enabling the batch readymode permits the control system to prepare a batch and retain it in theweigh hopper until the mixer is finished with the batch it is currentlymixing and ready to receive the new batch)

[0038] A recipe must be designated for use in the current blendingoperation. This recipe is either entered at the time by a user at thekeyboard and/or touchscreen or a previously entered and stored in thecomputer system is utilized. If a recipe is entered and used for thecurrent blending operation, it may be stored for later use. Furthermore,a recipe can be entered and stored without the need for utilizing it atthe time of entry. Since the storage of a recipe in a computer system120 requires storage space, the number of different recipes stored inthe storage system is only limited by the storage capacity of thecomputer system 120. In an effort to limit storage use, systems may, forexample, implement a limitation of fifty recipes. A collection ofrecipes is stored in a computer system 120 where the recipes can bedeleted, adjusted, or edited, new recipes may be added, and old recipesmay be recalled for use in the current blending operation. In apreferred embodiment, a new recipe may be entered by a user, or anpreviously created and stored recipe maybe loaded while the computersystem 120 of the blender system 10 is controlling the metering andblending of an unrelated recipe.

[0039] The blender control system 10 makes a batch of a recipe by thecomputer system 120 controlling the metering of materials from thedifferent hoppers based on the current recipe formula and current optionsettings. The computer system 120 determines the metering, or the feedtime, by calculating the target weight of each hopper (ingredient),where the target weight is derived from the relationship between thedesired batch weight and the correlated hopper. The calculation may alsoinclude an offset for an initial target weight percentage; where theinitial target weight is intended to incorporate the standard deviationof the feeder. As described above, this calculation permits feweroverfills by intentionally under filling. As filling is an iterativeprocess, the feed time calculation also incorporates feedback of thecurrent state of the system thereby adjusting the amount of materialremaining to be metered. For example, if in a recipe the ingredient inhopper one is ten percent (10%) of the batch weight and the batch weightis one hundred (100) pounds, then the target weight is ten pounds (10lbs). When the calculation is first made if an initial percentage hasbeen entered of eighty percent (80%) (to intentionally undershoot) thenthe calculation determines the feed time based on eighty percent (80%)of ten pounds (10 lbs). If the feeder is calibrated to one pound persecond (1 lb./sec) then, the feed time will be eight (8) seconds. Thecontrol system will then meter the appropriate feeder for eight (8)seconds. Feed time for remaining meters of this hopper (in thissequence) incorporates the amount of material already fed. If the weighhopper is measured and weighs seven and one half pounds (7½ lbs.) thenthe remaining amount of material to be fed is two and one half pounds(2½ lbs.), which would correspond to two and one half seconds (2½ sec.).Initial target percentage is only incorporated on the first metering ofthe ingredient per batch.

[0040] In a preferred embodiment, the execution of automated controlsystem to make a batch would proceed in the following steps (as show inFIG. 4):

[0041] In Step S0, the program execution awaits a command. If thecommand is given to mix a batch then the program execution begins thesteps necessary to mix a new batch and continues to the next step.

[0042] In Step S1, a recipe is chosen. As indicated above, either a newrecipe may be entered at that time or a previously entered and storedrecipe may be loaded from the computer system 120 storage. As indicatedabove, if a recipe is entered at that time then the recipe mode and thecomposition of the different ingredients is entered. Once a recipe ischosen and loaded or entered, any adjustments made to the recipe, anyrecipe options have been entered, and the batch size has been entered,the program proceeds.

[0043] In Step S2, the target weight of the current ingredient iscalculated. The computer system 120 derives the target weight from thedesired batch size and the ratio of the ingredient to the target weight.For example, if the batch size is one hundred (100) kgs. and the currentingredient's amount, in percentage mode, is twenty percent (20%), thenthe target weight is twenty (20) kgs.

[0044] In Step S3, the weigh hopper is cleared. In a preferredembodiment, the program follows this short algorithm:

[0045] In Step S3 a, the weigh hopper is weighed.

[0046] In Step S3 b, if the weight of the weigh hopper is equivalent to,or greater than, a pre-stored empty weight value, then executionproceeds to Step S4. Otherwise execution proceeds to Step S3 c.

[0047] In Step S3 c, the weigh hopper is emptied by conventionalmethods.

[0048] In Step S3 d, the weigh hopper is weighed.

[0049] In Step S3 e, if the weight of the weigh hopper is equivalent to,or greater than, a pre-stored empty weight value, then executionproceeds to Step S4. Otherwise execution proceeds to Step S3 f.

[0050] In Step S3 f, an alarm is given. In an alternative embodiment,the program continues to attempt to lower the weight of the weigh hopperby repeatedly dumping the weigh hopper until either the weight is loweror an operator interrupts the program.

[0051] In Step S4, the feed time is calculated. Taking intoconsideration the target weight, the initial percentage of target weight(only used on first iteration), the amount remaining to be fed (onlyused after first iteration), the feeder calibration of that hopper, andthe gate cycle time (FIG. 5), the feed time is computed in the followingsteps (as shown in FIG. 7):

[0052] In Step S4 a, the computer system 120 determines if this is thefirst time in this batch metering this ingredient. If it is the firsttime then it proceeds to Step S4 b. If it is not the first time in thisbatch metering this ingredient then it proceeds to Step S4 c.

[0053] In Step S4 b, the computer system 120 calculates the amount ofmaterial to be fed equal to the target weight minus any offset for‘initial percentage of target weight.’ Execution continues to Step S4 d.

[0054] In Step S4 c, the computer system 120 calculates the amount ofmaterial to be fed equal to the target weight minus amount of materialalready fed. Execution continues to Step S4 d.

[0055] In Step S4 d, the computer system 120 calculates the feed timerelating the amount of material to be fed with the calibration of thisfeeder.

[0056] In a preferred embodiment, the computer system 120 willincorporate offsets for gate cycle time. If in the gate cycle doublingembodiment, then execution proceeds to Step S60 (described below).

[0057] In Step S4 e, the computer system 120 recalculates the feed timeincluding a gate cycle time offset.

[0058] In Step S5, the feeder is metered for the feed time calculated inthe previous step.

[0059] In Step S6, the weigh hopper's weight is measured to determinethe amount of material that was actually fed.

[0060] In Step S7, the weigh hopper's weight is compared to the targetweight. If it is less than the target weight then the program executionreturns to Step S4. Otherwise the program execution proceeds to the nextstep.

[0061] In Step S8, the weigh hopper's weight is compared to the batchweight. If it is greater than the batch weight then execution proceedsto Step 8 a where the program dumps the current batch and Step 8 balarms appropriately. Otherwise, program execution continues to the nextstep.

[0062] In Step S9, the recipe is checked to see if all of theingredients have been metered. If there any more material (feeders) tobe metered then program execution returns to Step S2. Otherwise theprogram execution proceeds to Step S10.

[0063] In Step S10, the material in the weigh hopper is emptied into themixing chamber.

[0064] In Step S11, the program execution is completed for this recipebatch. In a preferred embodiment the program will return to SO to feedand blend additional recipes or additional batches of this recipe.

[0065] Depending on the setting, the calculation of feed time might alsoincorporate offsets required to compensate for a gate cycle time. If agate cycle time (the time to open and close a gate) is larger than afeed time then the gate will not open and no material will be fed. Inthis method, the number of remeters is calculated (in that batch forthat ingredient), and after an established number of retries, the gatecycle time is temporarily doubled prior to offsetting the feed time. Themethod of doubling the feed time is shown in FIG. 5 and incorporates thefollowing steps (FIG. 5):

[0066] In Step S60, the program has calculated the feed time in Step S4and the program execution continues to Step S61.

[0067] In Step S61 the computer calculates how many times in this batchthis feeder has attempted to retry feeding.

[0068] In Step S62 if the number of retries is equal to, or greaterthan, the value stored for the ‘number of retries before doubling’, thenthe execution continues to Step S63. Otherwise execution proceeds toS64.

[0069] In Step S63, the gate cycle time is recalculated and temporarilydoubled for this metering.

[0070] In Step S64 program execution returns to the main algorithm (FIG.4) and proceeds to Step S4 e.

[0071] In other embodiments, the feed time is calculated, in Step S63,equivalent to a predetermined amount of time in addition to the cycletime.

[0072] Although the preferred embodiment refers to an automated controlof a system, it is also preferable to provide the option of being ableto control the system manually. Furthermore, separate processes may becombined into a single process therefore reducing the number distinctprocesses and visa versa; process that are represented here as a singlestep, may be broken down into a plurality of steps. Additionally,although information storage is represented in the representative datastructures shown in FIGS. 2 and 3, information storage is not limited tothis format.

[0073] The above description and drawings are only illustrative ofpreferred embodiments of the present invention, and are not intended tolimit the present inventions thereto. Any subject or modificationthereof which comes within the spirit and scope of the following claimsis to be considered part of the present invention.

What is claimed as new and desired to be protected by Letters Patent ofthe United States is:
 1. A control apparatus for feeding a materialcomprising: first and second feed material storage means for holding aflowable, bulk solid material; weight measuring means for measuring aweight of said second feed storage means; material feeder means forcontrolling the delivery of said material from said first feed storagemeans to said second feed storage means; initial material feeder meansfor determining if it is a first metering of said material; feed timecalculation means for calculating a feed time corresponding to a feedamount for feeding said material through said material feeder means,wherein said feed amount is substantially equivalent to a firstpercentage of said target feed amount when said initial material feedermeans indicates that it is said first metering and corresponds to asecond percentage of said target feed amount when said initial materialfeeder means indicates that it is not said first metering; and feed timerecalculation means for recalculating a feed time corresponding to saidfeed time plus any feeder cycle offset.
 2. The control apparatusaccording to claim 1, further comprising: reattempt calculation meansfor calculating the number of times that said material feeder means isrequested to deliver said material, reattempt comparison means forcomparing result of said reattempt calculation means to determine if itsubstantially equivalent to a retry number; wherein it is determinedthat said result is substantially equivalent to said retry number, saidfeeder cycle offset is substantially equivalent to a second offset ornot substantially equivalent to said retry number, said feeder cycleoffset is substantially equivalent to zero.
 3. The control apparatusaccording to claim 2, wherein said first percentage of said target feedamount is preset and corresponds to the accuracy of said material feedermeans.
 4. The control apparatus according to claim 2, further comprisinga material feeder calibration means for measuring the accuracy of saidmaterial feeder means.
 5. The control apparatus according to claim 4,wherein said first percentage of said target feed amount corresponds tothe measurement of said material feeder calibration means.
 6. A controlapparatus for mixing materials, comprising: recipe means for maintainingrecipe information comprising a plurality of flowable, bulk solidingredient materials; plurality of first and second feed materialstorage means for holding a flowable, bulk solid material; weightmeasuring means for measuring a weight of said second feed storagemeans; plurality of material feeder means for controlling the deliveryof said selected material from said selected first feed storage means tosaid second feed storage means; initial material feeder means fordetermining if it is a first metering of said selected material; feedtime calculation means for calculating a feed time corresponding to afeed amount for feeding said selected material through said selectedmaterial feeder means; wherein said feed amount is substantiallyequivalent to first percentage of said selected target feed amount whensaid initial material feeder means indicates that it is the firstmetering or a second percentage of said selected target feed amount whensaid initial material feeder means indicates that it is not a firstmetering; and a feed time recalculation means for recalculating a feedtime corresponding to said feed time plus any feeder cycle offset. 7.The control apparatus according to claim 6, further comprising: recipecomplete means for determining if all of said materials for said recipehave metered.
 8. The control apparatus according to claim 7, whereinsaid second percentage of said target feed amount substantiallycorresponds to said selected target meter minus the results of saidweight measuring means.
 9. The control apparatus according to claim 8,further comprising: reattempt calculation means for calculating thenumber of times that said selected material feeder means is requested todeliver said selected material, reattempt comparison means for comparingresult of said reattempt calculation means to determine if itsubstantially equivalent to a respective retry number, and ifsubstantially equivalent to said respective retry number then saidfeeder cycle offset is substantially equivalent to a second offset; orif not substantially equivalent to said retry number then said feedercycle offset is substantially equivalent to zero.
 10. The controlapparatus according to claim 9, wherein said first percentage of saidtarget feed amount is preset and corresponds to the accuracy of saidselected material feeder means.
 11. The control apparatus according toclaim 9, further comprising a material feeder calibration means formeasuring the accuracy of said selected material feeder means.
 12. Thecontrol apparatus according to claim 11, wherein said first percentageof said target feed amount corresponds to the measurement of saidselected material feeder calibration means.
 13. A control apparatus forfeeding a material comprising: a first and second feed material storagethat holds a flowable, bulk solid material; a first material feeder thatcontrols the delivery of said material from said first feed storage tosaid second feed storage; and a programmed computer that calculates afeed time to feed said material through material feeder to reach a feedamount, wherein said feed amount is a first percentage of a target feedamount if it is the first metering of said material and a secondpercentage if it is not the first metering of said material, thatrecalculates said feed time to include a feeder cycle offset, that sendselectronic signals to said first material feeder to indicate the openingand closing of said first material feeder, that calculates the number oftimes that said opening signal is sent to said first material feeder,and that receives a weight signal from said second feed materialstorage.
 14. The control apparatus according to claim 13, wherein itsaid programmed computer calculates said first percentage of said targetfeed amount is corresponds to the accuracy of said material feeder. 15.The control apparatus according to claim 14, wherein said programmedcomputer further comprises: computing a second percentage of said targetfeed amount corresponding to said weight of said second feed storagecompared with said target feed amount.
 16. The control apparatusaccording to claim 15, wherein said programmed computer furthercomprises: comparing a retry number to said number of times an opensignal is sent to said first material feeder and if said retry number issubstantially equivalent to said number of times an open signal is sentto said first material feeder the feeder cycle offset is substantiallyequivalent to a cycle time increase and if said retry number is notsubstantially equivalent to said number of times an open signal is sentto said first material feeder the feeder cycle offset is substantiallyequivalent to a cycle time increase.
 17. The control apparatus accordingto claim 16, wherein said first material feeder is a slide gate.
 18. Thecontrol apparatus according to claim 17, further comprising: a secondmaterial feeder that controls the delivery of said material from saidsecond feed storage to a third material feed storage.
 19. The controlapparatus according to claim 18, wherein said second material feeder isa dump gate.
 20. The control apparatus according to claim 18, whereinsaid programmed computer sends electronic signals to said secondmaterial feeder to indicate the opening and closing of said secondmaterial feeder.
 21. The control apparatus according to claim 16,further comprising: a feed delivery mechanism that delivers materialfrom said first material feeder to said second feed material storage.22. The control apparatus according to claim 21, wherein said feeddelivery mechanism is a feed tube.
 23. The control apparatus accordingto claim 21, wherein said third feed storage is a mixing tank.
 24. Amethod for controlling the cyclical feeding of material through a feedercomprising the steps of: (a) calculating a target feed amount for aflowable, bulk solid ingredient material; (b) emptying a hopper; (c)calculating a feed amount substantially equivalent to a percentage ofsaid target feed amount; (d) calculating a feed time to feed said feedamount of said material through a feeder to said hopper; (e)recalculating said feed time to include a feeder cycle offset; (f)feeding said feeder for said feed time; (g) generating a weight signalindicative of the amount of said material in said hopper (h) calculatingsaid feed amount substantially equivalent to said target feed amountoffset by said weight signal; (i) calculating said feed timesubstantially equivalent to feed said feed amount of said materialthrough a feeder to said hopper; (j) recalculating said feed time toinclude said feeder cycle offset; and (k) feeding said feeder for saidfeed time.
 25. The method of claim 24, further comprising the step of:(l) repeating steps (g)-(k) until said weight signal is substantiallyequivalent to said target feed amount.
 26. The method of claim 25,further comprising the steps of: calculating accuracy of said feeder;and calculating before step (c) said percentage based on said accuracyof said feeder.
 27. The method of claim 26 further comprising the stepsof after step (i) and before step (j): storing a retry valuesubstantially equivalent to the number of times that step (i) isexecuted for said material; and calculating said feed time offset tocorrespond to a preset gate cycle increase if said retry value issubstantially equivalent to a retry number and calculating said feedtime offset to correspond to a zero if said retry value is notsubstantially equivalent to said retry number.
 28. The method of claim27 further comprising the step of: repeating steps (a) through (1) untilsubstantially all said materials of a recipe are fed.
 29. A method ofcontrolling a feeder, comprising the steps of: (a) calculating a targetfeed amount for a flowable, bulk solid ingredient material; (b)calculating a feed amount substantially equivalent to a percentage ofsaid target feed amount, where said percentage corresponds to theaccuracy of a feeder; (c) calculating a feed time to feed said feedamount of said material through a feeder to a hopper; and (d)recalculating said feed time to include a feeder cycle offset.
 30. Themethod of controlling a feeder in claim 29, further comprising:calculating said feed time offset to correspond to a preset gate cyclefactor if a gate cycle time of said feeder is longer than said feed timeand calculating said feed time offset to correspond to a zero if saidgate cycle time of said feeder is not longer than said feed time.